Method of producing needled felts



1966 M. M KEw ETAL METHOD OF PRODUCING NEEDLED FELTS 3 Sheets-Sheet 1Filed Jan. 11, 1965 FIGI.

DIRECTION OF FILLING AND BATT FIBERS FIGZ.

WARP MACHINE DIRECTION DIRECTION OF ADVANCE Jan. 25, 1966 McKEw ETALMETHOD OF PRODUCING NEEDLED FELTS 3 Sheets-Sheet 2 Filed Jan. 11, 1963CARDING MACHINE FIGJZ.

LAPPING MACHlNE Jan. 25, 1966 M. M KEW ETAL METHOD OF PRODUCING NEEDLEDFELI'S 3 Sheets-Sheet 3 Filed Jan. 11, 1963 United States Patent3,230,599 METHOD OF PRODUCING NEEDLED FELTS Marshall McKew, SchodackCenter, and Francis L.

McKone, Albany, N.Y., assignors to Huyck Corporation, Stamford, Conn., acorporation of New York Filed Jan. 11, 1963, Ser. No. 250,806 7 Claims.(Cl. 28-722) This invention relates to a novel felt construction for usein a paper making machine and to methods of and apparatus for producingthe same. The highly improved felt is produced by needling a batt offibers to a base fabric under conditions insuring high tensile strengthof the felt in both'the machine direction and the cross machinedirection. For this purpose it has been found highly important toprovide a special relationship between the barbs of the felting needlesand the directions in which the warps and wefts of the base fabricextend-and the general direction in which the longitudinal axis of thefibers of the batt extend.

Heretofore, in needling a batt of fibers to a base fabric, for theproduction of a paper making felt, the importance of maintaining-thespecialrelationship between the directions in which the barbs of theneedles, the warps and wefts of the base fabric, and the fibers of thebatt extend, as contemplated by the present invention, has not beenappreciated. In the conventional practice of needling a fiber batt to abase fabric, the felting needles have usually been provided with barbsextending in three or more directions from'the axis of each needle usedin a needling machine. Even when needles have been used that have barbspointing in one one or two directions, there has no appreciation oftheneed for alining the needles so .as to point all of the barbs incertain specific directions. Thus, no particular'attention'has been paidto the directions in which the barbs of one needle, of the multiplicityof needles used in aneedling machine, extend in relation to the barbs ofother needles of the group. Furthermore, in those instances in whichsome effort may have been made to direct the barbs of the variousneedles in some definite relationship to each other, the barbs of thevarious needles have not been pointed in the direction or directionsfound to be essential, for the purposes of the present invention, inrelation to the warps and wefts of the base fabric, and no attention hasbeen paid to the relationship between the direction in which the barsextend and the general direction in which the fibers of the batt extendor are oriented.

In accordance with the preferred embodiments of the present inventionthe barbs provided on each needle extend in only one direction, or atmost two directions, from the longitudinal axis of the needle. Thus aneedle having a triangular cross-section in the barbed region thereofwill have the barbs extending outwardly from the axis of the needle atonly one corner or edge of the triangular configuration, or will havethe barbs similarly extending outwardly from two corners or edges of thetriangular configuration. When such needles are used in a needlingmachine, care is exercised to have all of the barbs on the multiplicityof needles extend in substantially the same direction or the same twodirections.

Also, according to the present invention,.the direction in which thebarbs extend from the needles should bear a quite definite relationshipto the direction in which the warps, the wefts or filling yarns, and thelongitudinal axes of the batt fibers extend. When the needle is of suchcharacter that its barbs extend only in one direction, this should beparallel to the warps and perpendicular to the wefts and to the generalor major direction in which the batt fibers extend. It'will beappreciated that the batt fibers are not strictly linear but have a wavyconfiguration. Therefore, orientation of the fibers will be understoodas referring to the general longitudinal axis of the fibers; Also itwill be appreciated that in the carding of fibers it is not possible orpracticable to align their axes in the desired direction. However, inaccordance with the present invention it is highly desirable to alignthe axes of the fibers to the extent of at least 70% in the specifieddirection. If the needles employed have barbs extending in twodirections, these should preferably be at an angle of at least to eachother and they should preferably be pointed at not more than 30 to thedirection in which the warps extend, and preferably at least 60 to thedirection in which the wefts and the general longitudinal axes of thebatt fibers extend. It will be appreciated, however, that the benefits:of the invention may be achieved to a substantial extent if theangularrelationships specified are varied slightly. Thus if the bars areso disposed as to point in a direction of as much as 35 to the warpdirection and as little as 55 to the weft or filling direction,substantial benefits will be derived over the results obtained when someor all of the barbs are pointed at an angle of 45 or more to thedirection of the warps. In-the case of needles having a barbed sectionof triangular cross-section, as described above, the barbed portion ofthe needle preferably forms an equi lateral triangle in cross-section.

In speaking of warps, it should be understood that variety of otherconfigurations, such as circular, oval,.

diamond-shaped or the like, so long as the barbs provided are adapted tobe directed either parallel with the warps of the base fabric or at anangle of not more than 35 and preferably not more than 30 to thedirection of the warps of the base fabric.

In some instances it is possible to provide each needle with barbsextending in more than two directions from the axis of the needle. Thusin the case of a needle having a barbed portion of hexagonalcross-section it ispermissible to have the barbs extending outwardlyfrom' four of the corners, but these should be so arranged that when theneedles are attached to the reciprocating head of the needling machine,all of the barbs will preferably extend at angles of 30 to the warpdirection and at 60 to the filling or weft direction, and also thedirection of orientation of the batt fibers. Similarly, if the barbedportions of the needles are of octagonal cross-section, the barbs mayextend outwardly from four of the corners that are so disposed, when theneedles are mounted in the reciprocating head of the needling machine,that the barbs will point in directions of 22.5 to the direction-of thewarps and in directions of 675 to the direction of the wefts and thedirection of orientation of the batt fibers.

By performing the needling operation in accordance with the presentinvention, the resulting felt has a high tensile strength in the machinedirection, and also a higher than usual tensile strength in the crossmachine direction. The preservation of tensile strength in the machinedirection results from the minimum damage done to the warp threads, byvirtue of having the needle barbs extend in a direction parallel with,or at an angle of preferably not more than 30 to the warps; Improvedtensile strength in the cross machine direction results from the factthat any cutting or nicking of the wefts or filling yarns is more thanoffiset by the batt fibers which are firmly secured to the wefts andextend in the Weft direction to add to the tensile strength in thatdirection. In this connection it should be noted that any tendency ofthe needle barbs to cut into, and partially sever, the wefts or fillingyarns is minimized by the pick up of batt fibers by the barbs before thelatter pass through the normal path of the wefts. This tends to deflectthe wefts or filling yarns sufiiciently to avoid serious cutting.Moreover, whenever cutting or nicking of the wefts does take place, thefibers of the batt which are then firmly retained by the wefts andbridge the cuts or nicks formed in the latter, serve to supplant thetensile strength lost through the partial severance of the wefts.Moreover, the present invention reduces fiber shedding to a minimum.This is a highly desirable characteristic of the resulting felt.

With the foregoing objects and purposes in view the invention will nowbe described in further detail in reference to the accompanyingdrawings, in which:

FIG. 1 is a diagrammatic view, showing on an enlarged scale, theconstruction of the base fabric and the relative position of a number ofbarbed needles in applying the fibers of the batt thereto;

FIG. 2 is a schematic view, as a cross-section through the base fabricand a layer of batt fibers thereon in a direction parallel with the Weftor filling yarns, and shows two of the barbed needles in their lowermostposition;

FIG. 3 is a schematic view, similar to FIG. 2, but showing across-section through the base fabric and batt fibers in a direction atright angles to that shown in FIG. 2;

FIG. 4 is a greatly enlarged cross-sectional view through the barbedportion of one form of needle that may be used, the cross-section beingtaken at different levels to show the barbs which are located atdifferent elevations along the needle;

FIG. 5 is an enlarged elevational view of a typical needle that may beemployed in accordance with the invention;

FIG. 6 is an enlarged cross-sectional view through the barbed portion ofthe needle, taken along the line 66 of FIG. 5;

FIG. 7 is a view similar to FIG. 6, but taken along the line 77 of FIG.5;

FIGS. 8 and 9 are views similar to FIGS. 6 and 7, respectively, butshowing needles having a circular crosssection in the barbed region;

FIGS. 10 and 11 are cross-sectional views, taken at different elevationsthrough needles having barbed portions of oval and diamond-shapedcross-section, respectively;

FIG. 12 is a diagrammatic view illustrating the relationship between acarding machine and a lapping machine employed for the production ofa'multi-layered batt having its fibers all extending in substantiallythe same direction; and

FIG. 13 is a schematic view of a needling machine that may be employedin accordance with the invention.

It will be understood that the base fabric, schematically shown in FIG.1, may be produced of any desired width and length from yarns of anysuitable character. They may be formed of wool, or of any other fibersconventionally employed in the production of paper machine felts. If thefabric is woven fiat, the warps in the loom will be positioned in themachine direction of the felt to be produced therefrom, while the weftsor filling yarns in the loom will be positioned in the cross machinedirection. On the other hand, if the fabric is woven in endless fashionthe loom warps will extend in the cross machine direction and the loomwefts in the machine direction of the belt-like felt being produced. Forthe purposes of the further discussion of the invention, the term warpshall be understood as indicating the yarns which extend in the machinedirection and the term weft or filling shall be understood as referringto the yarns extending in the cross machine direction.

While the base fabric may be of any of a variety of different weaves,the form shown in FIGS.'l, 2 and 3 is of such a character that the warps10 pass over a single weft or filling yarn 11 and then under the nextthree filling yarns, with this pattern being repeated throughout thelength of the fabric. Similarly the wefts pass under one warp and thenover three warps in a repetitive manner across the width of the fabric.This serves to position the major portion of the wefts at the topsurface of the fabric and the major portion of the warps at the bottomsurface of the fabric. As the fabric is being advanced in the machinedirection through a needling machine of any of a variety of conventionalforms, a batt 12 formed of multi-layers of fibers, largely orientedsubstantially in the direction of the filling yarns, is applied to theupper face of the fabric. In the region of the needling machine in whicha reciprocating head, or a plurality of such heads, is provided a largenumber of needles 13 is forced downwardly through the batt and throughthe base fabric. The barbs of the needles will carry portions of groupsof fibers downwardly and will leave them in substantially U-shaped loopform, as indicated at 12a in FIG. 2, to present parallel leg portionsinplanes perpendicular to the directions in which the barbs extend fromthe axes of the needles, or parallel with the direction of orientationof the fibers. It will be appreciated that in the actual finalproductthe loops of fibers so produced will have their legs much closertogether and more nearly parallel than is shown in the enlargedschematic view of FIG. 2. It will be understood that the needles 13 areprovided in a plurality of rows which extend completely across the widthof the material to be needled. In plan, the arrangement of the needlesin relation to the warp and filling yarns of the base fabric may be asschematically indicated in FIG. 1. The reciprocating head or headscarrying the needles will be reciprocated at a suitable speed through adistance of say 3 inches, to carry the pointed ends of the needlesdownwardly through the batt and the base fabric, from a point above thebatt to a point about /2 inch below the base fabric.

111 FIGS. 1, 2 and 3 the needles are shown as having their barbedportions of triangular cross-section, with the barbs 13a of all needlespointing in a direction parallel with the warps 10 and perpendicular tothe wefts or filling yarns 11. These barbs are also pointed in adirection substantially perpendicular to the lengthwise orientation ofthe fibers of the batt. The barbs provided in the needles may be of avariety of different forms, but: it has been found desirable to makethem of the so-called! A type. This, as best shown in FIG. 3, makes itpossible for a barb to receive a plurality of batt fibers without dangerof having the fibers wedged intothe upper end of the barb opening. Thus,when the needles are moved upwardly the batt fibers will tend to remainin the positions to which they have been forced by the downward movementof the needles. The fibers of the batt will not become wedged in thebarb openings of the needles.

In some instances, certain of the needles will be found to carry thehbarbs into direct engagement with the filling yarns, with some resultantnicking of these yarns, as indicated for one of the needles shown inFIG. 3. However the fact that the barbs, at the time of their engagementwith the filling yarns, carry a number of batt fibers downwardly withinthe barb opening tends to minimize the extent of cutting or nicking ofthe filling yarns, and also tends to leave the batt fibers, so carried,in a: posit-ion within the filling yarns and firmly attached thereto.This tends to minimize any weakening of the cross; machine directionstrength of the finished felt structure. In fact, the orientation of thebatt fibers in the cross machine direction builds up a certain amount ofstrength in that direction.

It will be understood that in the course of operatiorn of the needlingmachine, the base fabric andthe batt Willi be continuously advanced inthe direction of the warps, and this movement of the material preferablyis such as to carry the wefts and the batt fibers toward the barbs ofthe needles. While this increases the tendency of the barbs on the sidesof the needles that are opposite the direction of motion to cut into ornick the filling yarns, it has been found to improve the bonding of thebatt fibers to the base fabric in the course of the needling operation.The net result appears to be an improvement of the end product produced,as compared with one formed by having the barbs of the needles pointedin the opposite direction, i. e., in the direction in which the basefabric and batt are being advanced. However, quite satisfactory resultsare obtained if this reverse arrangement of the barbs is employed.

In order to insure the desired extent of needling of the batt fibersinto the base fabric, it is preferable to cycle the material through theneedling zone a number of times. The number of passes required to bringabout the desired attachment of the batt to the base fabric willdepend,in fact, upon the depth of penetration and density of needling, i.'e.penetrations-per square area, thelatter being governed by the relativespeeds of the reciprocating head of the needling machine and the advanceof the work.

In some instances it may be found desirable to apply a batt of fibers toboth surfaces of the base fabric. When this is desired, a batt of fibersis first applied to one surface and the resulting product is theninverted and a second batt is applied to and needled to the oppositeface of the base fabric in the same manner as explained above.

Referring now to FIGS. 4-7 inclusive, there is shown a form of barbedneedle. having a a triangular crosssection in the barbed region thereof,with barbs extending in two different directions from the axis of theneedle. The general form of the needle is shown in elevation in FIG. 5.This is a conventional form which may also be employed in connectionwith the above described, having barbs extending in only one directionfrom the axis thereof. Needle 15 of FIG. 5, having its upper portion ofcircular cross-section and bent over at 15a to facilitate its clampingin the head of a needling machine, has a barbed portion 15b oftriangular cross-section. In this portion of the needle there areprovided three barbs 15c extending in one direction, and three similarbarbs'15d extending in another direction, which is at an angle of 120 tothe direction of the barbs 150. In the use of this type of need-1ein-the needling machine, care is exercised to dispose the surface 15eparallel with the direction in which the warps of th base fabric extend.In this way, as best shown in FIG. 4, the two sets of barbs will pointin directions at an angle of 30 to the direction in which the warpsextend. As a result they will be directed at an angle of 60 to thedirection in which the wefts and the batt fibers extend and at an angleof 120 in relation to each other. As indicated-in FIGS. 4 and 5, thebarbs 15c are preferably located at a slightly different elevation thanthe barbs 15d. One of these sets of barbs points in the generaldirection in which the material is being advanced, and the other setpoints toward the advancing wefts and batt fibers, not directly but atan angle of 60 thereto.

While the strength of the fabric in the machine direction is notmaintained as effectively in the use of needles having barbs extendingin two directions, as is accomplished with barbs extending in only onedirection parallel with the warp direction, the overall strength of thefabric is nevertheless maintained at a high value. The disposition ofthe barbs at an angle of not more than 30 to the warps prevents anyserious damage to the warps even if the barbs are brought into cuttingrelation with a portion of the warp yarns. It has been found that withthis angular relationship, either the needles or the warp threads may bedeflected sufficiently by the co-action of the tapered, pointed ends ofthe needles with the side 6 surfaces of the warps to prevent seriouscutting of the warps by the barbs.

FIGS. 8 and 9 illustrate a modified form of the barbed portion of theneedle. These views may be considered as taken along the lines 66 and7-7, respectively, of FIG. 5, with the barb portion 15b of the needlebeing circular in cross-section. In this modified form of needle therewill be provided a plurality of barbs 16a pointing in one direction,which will be disposed at 35 or less to the warp direction of the basefabric, and another series of barbs 16b pointed in a differentdirection, but not more than 35 to the direction of the warps of thebase fabric. Thus, one set of barbs may be pointed at such an angle tothe direction in which the fabric is being advanced, and the other setof barbs may be pointed in a corresponding direction against that inwhich the fabric is being advanced.

As has been indicated, the barbed portion of a needle in accordance withthe invention may have a variety of different cross-sections in lieu ofthe triangular and circular forms illustrated. The needle may have abarbed portion of oval cross-section, diamond-shaped cross-section, or avariety of other polygonal cross-sections. However, whatever thecross-section may be, it is important that all of the barbs extend insuch directions that when the needle is clamped in the head of theneedling machine, none will be disposed at an angle of more than 35 andpreferably not more than 30 to the warp direction. As typical of otherconfigurations of the barbed portion of the-needle, reference may bemade to FIGS. 10 and-11. Thus, FIG. 10 shows a needle having an ovalcross-section in the barbed region, with barbs 16c pointing toward theadvancing wefts and barbs 16d pointing away from the advancing wefts, atan angle of thereto. In this case the barbs are pointed at angles thatare apart in relation to each other. FIG. 11 shows a needle having adiamond-shaped cross-section in the barbed region, with barbs 16c and 16pointing in the directions explained for barbs 16c and 16d,respectively. Whenever the barbs on a needle are arranged to point indifferent directions from the axis of the needle, it will normally benecessary or desirable to have them pointed in opposite directionsin-relation to the direction of advance of the fabric and batt throughthe needling machine; By opposite directions it is'simply meant thatsome are pointed in the direction of advance of the material whileothers are pointed against the direction of advance of the material,with the barbs pointing in the two directions being disposed at not morethan 35 to the warps of the base fabric and to the direction of advanceof the base fabric and batt.

To bring about the orientation of the batt fibers in a directionsubstantially transverse to the length of the batt being formed, acombination of machines may be employed. As shown in FIG. 12, theoriginal fibrous material, with no particular orientation may first befed to a carding machine 18, which through its action serves to orientthe fibers to a high degree in the direction in which the fibrousmaterial is being advanced. This orientation of the fibers isschematically shown in FIG. 12 by the lines designated 19. Aftersuitable orientation of the fibers in this manner, a quite thin film ofthe same will be carried by a conveyor 20 through a lapping machine 21.The latter may be of a well-known conventional construction. It servesto pick up sections of the thin layered carded fibers and deposit suchsections on layers previously positioned crosswise of a conveyor belt22. The latter is continuously advanced in the direction indicated bythe arrow in FIG. 12, at such a rate that when the desired number oflayers have been built up on conveyor 22 the latter will have advanced adistance equal to the width of the single layers being delivered by theconveyor 20. Thus, if it is desired to form a batt having ten layers ofthe type delivered from the carding machine, the conveyor 22 should beadvanced at a rate equal to the width of a single layer on conveyor 20during precisely the time that the ten layers are built up on conveyor22. Since the latter is being continuously advanced, it will be apparentthat the fibers of the several layers being built up to form the battwill assume a slightly diagonal position in relation to each other. Thisresults in disposing the oriented fibers, that extend longitudinally ofthe single layer on conveyor 20, in directions substantially transverseto the multi-layered batt formed on the conveyor 22. They will, however,be oriented at a small angle to the true transverse direction of thebatt, as is indicated schematically by the lines 23. This, as stated, isdue to the fact that the conveyor 22 is being continuously advanced asthe multiple layers are being built up thereon.

The multi-layered batt formed on conveyor 22 may be delivered directlyto a needling machine for application to the upper surface of the basefabric in the manner explained above. However, this is not essential andthe two operations may be separately performed, if desired.

FIG. 13 schematically shows how the base fabric and the batt fibers aresupplied and advanced through the needling machine. The multi-layeredbatt 23 may be delivered, either directly from the lapping machine orfrom a roll, to a conveyor belt 24 and advanced downwardly with theupper run of this belt. The latter passes around a pair of rollers 25and 26, one of which may be driven by any suitable connections from adrive shaft connected with the needling machine. From the lower end ofthe downwardly moving run of the belt 24, the batt will be delivered tothe upper surface of the base fabric 27, which may suitably have itsfree ends clipped together into endless belt form. It is supported byrollers 23 and 29, and a number of intermediate rollers if desired. Oneof the rollers 28 and 29 may be connected with the drive shaft of theneedling machine to bring about continuous advance of the fabric in thedirection indicated by the arrow. The rate of advance will correspond tothe rate at which the batt is delivered to the fabric. As the latter isadvanced it is carried through the needling zone of the machine. This isschematically shown as including a plurality of rows of needles 31, 13such rows being shown, each row extending across the width of the basefabric. Needles 31 are mounted in a head 30 and are clamped in positionby means of a plate 32 that may be secured by screws or bolts 33 to thetop of the head. The latter is reciprocated in a vertical direction byconnections from the drive shaft of the machine, a part of suchconnections being schematically indicated at 34. In the region in whichthe needles act upon the batt and the base fabric, the latter may besupported by a plate 35, or the like, having suitable openings orpassages 35a therethrough, to permit the downward movement of theneedles 31 into a position in which the lower ends thereof are below theupper run of the fabric 27.

After the entire outer surface of the base fabric has been covered by acorresponding length of the batt, the latter may be severed by suitablecutting blades, and the supply of the batt material may be discontinued.As has been explained, the base fabric and the batt may be cycled anumber of times through the needling zone of the machine to insureeffective needling of the batt fibers to the base fabric.

While various embodiments of the invention have been described in somedetail, it will be understood that modifications of the same, other thanthose specifically referred to above, may be made within the scope ofthe invention as defined by the appending claims.

What is claimed is:

1. A method of producing a paper machine felt which comprises: forming abase fabric with certain yarns extending in the machine direction andother yarns extending in the cross machine direction of the felt,applying to one surface of said fabric a batt of fibers having themajority of the fibers thereof oriented in substantially the crossmachine direction, and needling said batt to said base fabricby needleshaving all of their fiber engaging barbs disposed at an angle of notmore than about 30 to the machine direction yarns.

2. A method of producing a paper machine felt which comprises: forming abase fabric with certain yarns extending in the machine direction andother yarns extending in the cross machine direction of the felt,applying to one surface of said fabric a batt of fibers having amajority of the fibers thereof oriented in substantially the crossmachine direction, and needling said batt to said base fabric by needleshaving all of their fiber engaging barbs disposed substantially parallelwith the machine direction yarns.

3. A method according to claim 1 in which said needles are formed withbarbs extending in only one direction from the axis of the needles, saidneedles being so disposed in the course of the needling operation as tohave their barbs extend in a direction substantially at right angles tothe direction of orientation of the majority of batt fibers.

4. A method according to claim 3 in which the base fabric and batt areadvanced in the machine direction as the fibers of said batt are beingneedled to said base fabric, the barbs of said needles being pointed ina direction opposite to that in which the fabric and batt are beingadvanced.

5. A method according to claim 1 in which each of said needles isprovided with barbs extending therefrom in directions disposed at anangle between about and in relation to each other, said needles being sodisposed in the course of the needling operation that all of their barbsextend in a direction of at least about 60 to the direction oforientation of the batt fibers.

6. A method of producing a paper machine felt as set forth in claim 1 inwhich at least 70% of the fibers of the batt are oriented insubstantially the cross machine direction as they are needled to thebase fabric.

7. A method of producing a paper machine felt as set forth in claim 1 inwhich said base fabric is woven and is advanced in the machine directionof the felt as the batt is applied and needled thereto.

References Cited by the Examiner UNITED STATES PATENTS 1,035,622 8/1912Maussner 2879 1,225,671 5/1917 Maussner 284 1,243,133 10/1917 Billington284 1,314,565 9/11919 'Billington 2-8-72.2 2,165,772 7/1939 Walsh et al161--80 2,588,228 '3/ 1952 Gates 2-8 72.2 2,943,379 7/1960 Faltz 28793,090,100 5/1963 Smith 28--72.2

DONALD W. PARKER, Primary Examiner.

RUSSELL C. MADER, Examiner.

1. A METHOD OF PRODUCING A PAPER MACHINE FELT WHICH COMPRISES: FORMING A BASE FABRIC WITH CERTAIN YARNS EXTENDING IN THE MACHINE DIRECTION AND OTHER YARNS EXTENDING IN THE CROSS MACHINE DIRECTION OF THE FELT, APPLYING TO ONE SURFACE OF SAID FABRIC A BATT OF FIBERS HAVING THE MAJORITY OF THE FIBERS THEREOF ORIENTED IN SUBSTANTIALLY THE CROSS MACHINE DIRECTION, AND NEEDING SAID BATT TO SAID BASE FABRIC BY NEEDLES HAVING ALL OF THEIR FIBER ENGAGING BARBS DISPOSED AT AN ANGLE OF NOT MORE THAN ABOUT 30* TO THE MACHINE DIRECTION YARNS. 